In order to develop stem and progenitor cell therapies for treating CNS diseases, it is important to be able to determine the fate of transplanted cells non-invasively over time, including the location, survival, and status of downstream cell differentiation. We propose to use two complementary modalities, magnetic resonance imaging (MRI) and bioluminescence imaging (BLI), to follow the fate (sites of injection, movements, survival, and differentiation) of transplanted cells in two complementary models of motor neuron disease (MND), i.e., a ricin-induced model as a localized, monophasic and a neurotropic Sindbis virus (NSV)-induced as a global, inflammatory disease model. Magnetically labeled and dual luciferase (Luc-BLI)-transducted glial restrictor precursors (GRPs) or embryonic stem cell-derived motor neurons (ESC-MNs) will be transplanted in the spinal cord of rats following the induction of MND disease. We hypothesize that ESC-MNs can improve functional recovery through formation of new motor neurons, while GRPs can neuroprotect host MNs and/or support transplanted ESC-MNs. In order to assess functional recovery, we will perform behavioral analyses, electrophysiologic measurements (motor-evoked potentials), and muscle mass measures, and will determine whether intraparenchymal or intrathecal injections are the optimal route of transplantation. We will use MRI to monitor the accuracy of cell injections, the extent of cell migration and intraparenchymal tissue distribution (white vs. gray matter), whereas dual luciferase reporter BLI will be used to report on the survival and enhancer (HB9) or promoter (GFAP)-driven lineage differentiation of transplanted cells. We hypothesize that accurate cell injections, extended migration distances, and the relative ratio of cell survival and downstream cell differentiation will correlate with the measured behavioral scores, electrophysiologic readouts, and total skeletal muscle mass segmentation measurements. In addition, we will test the feasibility of our novel artificial MRI reporter, lysine-rich protein (LRP) or its improved derivatives, to interrogate the fate of cells in a similar fashion as using the luciferase gene.